As the market competition becomes more and more intense, an inverter is required to an increasingly higher power, an increasingly smaller volume, and an increasingly lower weight. The higher the power of the inverter is, the higher the heat may be generated by the inverter. If heat is dissipated only by a heat dissipator itself, the volume of the heat dissipator may be inevitably large, which does not meet the market requirement. Therefore, it is necessary to use a forced air cooling to dissipate heat, and only in this way, the volume of the heat dissipator can be reduced, and the weight thereof can be lowered. It is inevitable to use fans when employing the forced air cooling, and the mounting positions of the fans directly influence the usage environment of the fans. Air inlets of fans of conventional products are generally exposed outside, which is adverse to prevent invasions by sand wind, and has a quite average heat dissipation effect.